Electromagnetic valve identification device and control unit including same

ABSTRACT

An electromagnetic valve identification device configured to realize individual identification of an electromagnetic valve while suppressing an increase in manufacturing cost. The electromagnetic valve identification device is mounted on an industrial machine, such as a construction machine or an industrial vehicle, configured to move a hydraulic actuator to perform work. The electromagnetic valve identification device includes: an inductance measuring circuit configured to supply an alternating current to a solenoid of an electromagnetic valve of a hydraulic device, the hydraulic device being configured to supply pressure oil to the hydraulic actuator to operate the hydraulic actuator; a calculating portion configured to calculate an inductance of the solenoid based on the alternating current supplied to the solenoid by the inductance measuring circuit; and a storage portion configured to store the calculated inductance of the solenoid as individual identification information of the electromagnetic valve.

TECHNICAL FIELD

The present invention relates to an electromagnetic valve identificationdevice configured to perform individual identification of anelectromagnetic valve mounted on an industrial machine, such as aconstruction machine or an industrial vehicle, and a control unitincluding the electromagnetic valve identification device.

BACKGROUND ART

Construction machines (such as hydraulic excavators and wheel loaders)and travelable industrial vehicles (such as forklifts) can performvarious types of work by moving attachments (such as buckets and forks).According to the construction machines and industrial vehicles havingsuch function, the attachments are moved by operating hydraulicactuators (such as hydraulic cylinders and hydraulic motors). Thehydraulic actuators are driven by being supplied with operating oil. Theindustrial vehicles include hydraulic devices configured to supply theoperating oil to the hydraulic actuators. In order to change a tiltingangle of a hydraulic pump and move a spool of a flow control valve, thehydraulic device includes a plurality of electromagnetic valves.

As with other devices, the electromagnetic valve may be required to bereplaced due to breakdown or the like and is actually replaced once in awhile. Typically, the electromagnetic valve of the hydraulic device isreplaced with a proper hydraulic device, and with this, the function ofthe hydraulic device is secured. Therefore, when replacing theelectromagnetic valve, it is preferable to use a proper product havingthe same function and quality as the electromagnetic valve equipped in aconstruction machine or industrial vehicle when the construction machineor industrial vehicle is assembled and manufactured. However, actually,electromagnetic valves that are improper products having low quality areused as replacement parts in some cases. In such cases, the hydraulicdevice cannot exert a desired function, and in the worst case, thehydraulic device and various devices of the industrial vehicle may bedamaged. In order to prevent the use of the improper product at the timeof replacement, for example, devices of PTLs 1 and 2 are known.

According to an identification device of PTL 1, IC chips are attached toreplaceable parts. Then, the identification device detects informationstored in the IC chips and determines whether the replaceable parts aregenuine products (proper products) or counterfeit products (improperproducts). Further, according to an improper part use prevention systemof PTL 2, part IDs are attached to replaceable parts, and the part IDsare input through an input unit. The input part IDs are transmitted to adata server through a wireless communication network, and whether or notthe input part IDs are part IDs of unused parts is determined. Thus, theimproper products are prevented from being used.

CITATION LIST Patent Literature

PTL 1: Japanese Patent No. 4399524

PTL 2: Japanese Laid-Open Patent Application Publication No. 2016-98528

SUMMARY OF INVENTION Technical Problem

According to the identification device of PTL 1, the individualidentification of the replaceable parts is performed based on theinformation stored in the IC chips, and therefore, the IC chips have tobe attached to the respective parts. In addition, in order to performthe individual identification, sensors configured to detect theinformation of the IC chips need to be arranged at various places. Thus,the number of parts increases, and this increases the manufacturingcost.

According to the improper part use prevention system of PTL 2, theindividual identification of the replaceable parts is performed byattaching the part IDs to the respective replaceable parts. Theindividual identification needs to be performed by transmitting the partIDs to the data server. Therefore, a wireless communication device andthe data server are necessary, and this increases the manufacturingcost.

An object of the present invention is to provide an electromagneticvalve identification device configured to perform individualidentification of an electromagnetic valve while suppressing amanufacturing cost.

Solution to Problem

An electromagnetic valve identification device according to the presentinvention is an electromagnetic valve identification device mounted onan industrial machine, such as a construction machine or an industrialvehicle, configured to move a hydraulic actuator to perform work. Theelectromagnetic valve identification device includes: an inductancemeasuring circuit configured to supply an alternating current to asolenoid of an electromagnetic valve of a hydraulic device, thehydraulic device being configured to supply pressure oil to thehydraulic actuator to operate the hydraulic actuator; a calculatingportion configured to calculate an inductance of the solenoid based onthe alternating current supplied to the solenoid by the inductancemeasuring circuit; and a storage portion configured to store thecalculated inductance of the solenoid as individual identificationinformation of the electromagnetic valve.

According to the present invention, the inductance of the solenoid ofthe electromagnetic valve is stored as the individual identificationinformation. Regarding the inductances of the solenoids, the inductanceof each solenoid has a specific value. However, typically, even whensolenoids are the same in winding number and wire diameter as oneanother, the inductances of the respective solenoids have differentnumerical values, i.e., the inductances of the respective solenoidsvary. Therefore, the inductance of the solenoid of the electromagneticvalve can be used as the individual identification information of theelectromagnetic valve. To be specific, the individual identification ofthe electromagnetic valve and a part including the electromagnetic valvecan be performed by mounting such electromagnetic valve identificationdevice on the industrial vehicle. Therefore, it is unnecessary to attachIC chips to electromagnetic valves and parts including theelectromagnetic valves mounted on industrial vehicles or attach IDs toelectromagnetic valves and parts including the electromagnetic valvesmounted on industrial vehicles to manage the electromagnetic valves andthe parts, in order to perform the individual identification of theelectromagnetic valves. Thus, the manufacturing cost can be suppressed.

In the above invention, the electromagnetic valve identification devicemay further include a replacement determining portion configured todetermine whether or not the electromagnetic valve has been replaced,based on a determination criterion in which whether or not theelectromagnetic valve has been replaced is determined by using theinductance calculated by the calculating portion.

According to the above configuration, whether or not the electromagneticvalve has been replaced can be determined by using the inductance of thesolenoid, i.e., the individual identification information. Therefore,whether or not the electromagnetic valve has been replaced can bedetermined by a simple configuration without attaching IC chips toelectromagnetic valves and parts including the electromagnetic valvesmounted on industrial vehicles or attaching IDs to electromagneticvalves and parts including the electromagnetic valves mounted onindustrial vehicles to manage the electromagnetic valves and the parts.

In the above invention, the determination criterion may include whetheror not a reference inductance of the solenoid and an actually measuredinductance of the solenoid are different from each other, the referenceinductance being calculated by the calculating portion and stored in thestorage portion in advance, the actually measured inductance beingcalculated by the calculating portion, and when the actually measuredinductance is different from the reference inductance, the replacementdetermining portion may determine that the electromagnetic valve hasbeen replaced.

According to the above configuration, whether or not the electromagneticvalve having the same inductance is being continuously mounted can bedetermined, i.e., whether or not the same electromagnetic valve is beingcontinuously mounted can be determined. When the same electromagneticvalve is not being continuously mounted, it can be determined that theelectromagnetic valve has been replaced at a certain time point.Therefore, whether or not the replacement work has been performed can besurely determined.

In the above invention, when a predetermined reference value settingcondition is satisfied, the calculating portion may calculate thereference inductance of the solenoid, and the storage portion may storethe reference inductance calculated by the calculating portion.

According to the above configuration, when the reference value settingcondition is satisfied after the electromagnetic valve has beenreplaced, the inductance of the replaced electromagnetic valve can benewly stored as the reference inductance. On the other hand, when thereference value setting condition is not satisfied, the referenceinductance cannot be reset. Therefore, it is possible to prevent a casewhere the reference inductance is freely changed, and theelectromagnetic valve is made to look as if it has not been replaced.

In the above invention, the determination criterion may include whetheror not the actually measured inductance calculated by the calculatingportion falls within a predetermined allowable range, and when theactually measured inductance falls outside the allowable value, thereplacement determining portion may determine that the electromagneticvalve has been replaced.

According to the above configuration, whether or not the electromagneticvalve has been replaced can be determined based on whether or not theinductance of the replaced electromagnetic valve, i.e., the actuallymeasured inductance falls outside the allowable range. Therefore, it ispossible to prevent a case where an electromagnetic valve having aninductance that falls outside the allowable range is adopted as areplacement part. It should be noted that the allowable range is, forexample, a range of manufacturing error (tolerance) of electromagneticvalves (for example, electromagnetic valves as proper products) that arenot the same as one another but can exert substantially the samefunction. With this, the replacement of the electromagnetic valve havingthe inductance that falls outside the allowable range can be found,i.e., the replacement of the electromagnetic valve that is an improperproduct, such as a counterfeit product, can be found.

In the above invention, the electromagnetic valve identification devicemay further include a resistance measuring portion configured to supplya direct current to the solenoid and measure a resistance value of thesolenoid. The determination criterion may include whether or not areference resistance value of the solenoid and an actually measuredresistance value of the solenoid are different from each other, thereference resistance value being measured by the resistance measuringportion in advance, the actually measured resistance value beingmeasured by the resistance measuring portion, and the replacementdetermining portion may compare the actually measured resistance valuewith the reference resistance value and determine whether or not theelectromagnetic valve has been replaced.

According to the above configuration, whether or not the electromagneticvalve has been replaced can be determined based on the resistance valueof the solenoid of the electromagnetic valve. When solenoids are thesame in winding number and wire diameter as one another, the resistancevalues of such solenoids vary less than the inductances of thesolenoids. Therefore, the type and the like of the electromagnetic valvecan be specified by comparing the resistance value of the solenoid ofthe electromagnetic valve with the reference resistance value. On thisaccount, by using the resistance value of the solenoid of theelectromagnetic valve in the individual identification together with theinductance of the solenoid of the electromagnetic valve, the individualidentification of the electromagnetic valves and the parts including theelectromagnetic valves can be performed more accurately.

An electromagnetic valve identification device according to the presentinvention is an electromagnetic valve identification device mounted onan industrial machine, such as a construction machine or an industrialvehicle, configured to move a hydraulic actuator to perform work. Theelectromagnetic valve identification device includes: a resistancemeasuring portion configured to supply a direct current to a solenoid ofan electromagnetic valve of a hydraulic device and measure a resistancevalue of the solenoid, the hydraulic device being configured to supplypressure oil to the hydraulic actuator to operate the hydraulicactuator; and a replacement determining portion configured to determinewhether or not the electromagnetic valve has been replaced, based on adetermination criterion in which whether or not the electromagneticvalve has been replaced is determined by using the resistance valuemeasured by the resistance measuring portion.

According to the present invention, whether or not the electromagneticvalve has been replaced can be determined by using the resistance of thesolenoid, i.e., the individual identification information. Therefore,whether or not the electromagnetic valve has been replaced can bedetermined by a simple configuration without attaching IC chips toelectromagnetic valves and parts including the electromagnetic valvesmounted on industrial vehicles or attaching IDs to electromagneticvalves and parts including the electromagnetic valves mounted onindustrial vehicles to manage the electromagnetic valves and the parts.In addition, typically, the above effects can be obtained only bychanging software or control logic without changing the hardwareconfiguration of a conventional control device. Further, the resistancevalue of the solenoid can be detected by a smaller number of parts thanthe inductance of the solenoid. Therefore, the determination based onthe resistance is lower in cost than the determination based on theinductance.

In the above invention, the determination criterion may include whetheror not a reference resistance value of the solenoid and an actuallymeasured resistance value of the solenoid are different from each other,the reference resistance value being measured by the resistancemeasuring portion in advance, the actually measured resistance valuebeing measured by the resistance measuring portion.

According to the above configuration, whether or not the electromagneticvalve has been replaced can be determined by comparing the resistancevalues.

A control unit according to the present invention includes: theabove-described electromagnetic valve identification device; and acontrol device mounted on the industrial vehicle and configured tosupply a current to the solenoid of the electromagnetic valve to controlan operation of the electromagnetic valve. The control device isconfigured to restrict the operation of the electromagnetic valve whenthe replacement determining portion determines that the electromagneticvalve has been replaced.

According to the above configuration, it is possible to prevent the useof the hydraulic device whose function is made low since, for example,the replaced electromagnetic valve is an improper product, or theelectromagnetic valve is replaced through an improper method.

Advantageous Effects of Invention

According to the present invention, the individual identification of theelectromagnetic valve can be performed while suppressing an increase inthe manufacturing cost.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a hydraulic circuit diagram showing the configuration of ahydraulic device including a control unit according to Embodiment 1 ofthe present invention.

FIG. 2 is a block diagram showing functional blocks of the control unitof FIG. 1.

FIG. 3 is an electric circuit diagram showing the configuration of anLCR measuring circuit included in the control unit of FIG. 2.

FIG. 4 is a flow chart showing the procedure of individualidentification processing executed by the control unit shown in FIG. 2.

FIG. 5 is a flow chart showing the procedure of reference valuemeasurement processing executed in a reference value measurement mode ofFIG. 4.

FIG. 6 is a flow chart showing the procedure of actually measured valuemeasurement processing executed in an actually measured valuemeasurement mode of FIG. 4.

FIG. 7 is a block diagram showing functional blocks of the control unitof Embodiment 2.

DESCRIPTION OF EMBODIMENTS

Hereinafter, control units 1 and 1A according to Embodiments 1 and 2 ofthe present invention will be described with reference to the drawings.It should be noted that directions stated in the following descriptionare used for convenience sake, and directions and the like of componentsof the present invention are not limited. Each of the control units 1and 1A described below is just one embodiment of the present invention.Therefore, the present invention is not limited to the embodiments, andadditions, deletions, and modifications may be made within the scope ofthe present invention.

Construction Machine and Industrial Vehicle

Construction machines and industrial vehicles as examples of industrialmachines perform various types of work by moving various attachments.Examples of the construction machines include hydraulic excavators,wheel loaders, cranes, skid steer loaders, and aerial work platformvehicles, and examples of the industrial vehicles include forklifts.These construction machines and industrial vehicles can perform work,such as excavating work and carrying work. For example, a hydraulicexcavator includes a bucket and performs excavation by the bucket.Further, the hydraulic excavator includes a travelable vehicle body andcan change an excavation position and carry, for example, excavated sandby making the vehicle body travel. In the hydraulic excavator configuredas above, the bucket is attached to the vehicle body through a boom andan arm. The hydraulic excavator performs excavating work by making thebucket, the boom, and the arm swing in front, rear, upper, and lowerdirections. Further, the hydraulic excavator makes the bucket, the boom,and the arm swing by hydraulic cylinders.

The hydraulic cylinder that is one example of a hydraulic actuatoroperates by being supplied with operating oil that is pressure oil. Tobe specific, the hydraulic cylinder expands or contracts in accordancewith a flow direction of the operating oil supplied thereto and operatesat a speed corresponding to a flow rate of the operating oil suppliedthereto. As above, the hydraulic cylinder is driven by the operating oilsupplied thereto, and the hydraulic excavator includes a hydraulicdriving apparatus 2 configured to supply the operating oil to thehydraulic cylinder.

Hydraulic Device

As shown in FIG. 1, the hydraulic driving apparatus 2 mainly includes ahydraulic pump device 11, a plurality of flow rate control devices 12,and a bleed-off valve 13. It should be noted that FIG. 1 shows only oneflow rate control device 12 located at a most upstream side among theplurality of flow rate control devices 12, and does not show the otherflow rate control devices 12. The hydraulic pump device 11 is configuredto discharge the operating oil to supply the operating oil to thehydraulic actuator. The hydraulic pump device 11 includes a hydraulicpump 21, a regulator 22, and an electromagnetic proportional valve 23.The hydraulic pump 21 is coupled to a driving source, such as an engine(not shown), and is rotated by the driving source. By this rotation, thehydraulic pump 21 sucks the operating oil from a tank 15 and dischargesthe operating oil to a main passage 16. The hydraulic pump 21 is avariable displacement swash plate pump and includes a swash plate 21 a.A tilting angle of the swash plate 21 a is changeable, and a dischargevolume of the hydraulic pump 21 changes by changing the tilting angle.The regulator 22 is attached to the swash plate 21 a having suchfunction. The electromagnetic proportional valve 23 is attached to theregulator 22. The regulator 22 is formed integrally with a casing of thehydraulic pump 21.

The regulator 22 is a mechanism configured to change the tilting angleof the swash plate 21 a and includes a servo piston (not shown). Theservo piston is coupled to the swash plate 21 a and can reciprocatealong an axis thereof. The servo piston configured as above can changethe tilting angle of the swash plate 21 a by changing a positionthereof. Further, the servo piston changes the position thereof inaccordance with pilot pressure p input thereto. The electromagneticproportional valve 23 configured to apply the pilot pressure p to theservo piston is connected to the regulator 22.

The electromagnetic proportional valve 23 is a so-called directproportion type electromagnetic valve and outputs pilot oil havingpressure corresponding to a current (discharge volume command current)input thereto. More specifically, the electromagnetic proportional valve23 is connected to the regulator 22, the tank 15, and a pilot pump (notshown). The electromagnetic proportional valve 23 includes a solenoid 23a. In accordance with a current supplied to the solenoid 23 a, theelectromagnetic proportional valve 23 adjusts a connection statusbetween the regulator 22 and the tank 15, an opening degreetherebetween, a connection status between the regulator 22 and the pilotpump, and an opening degree therebetween. To be specific, when a currentis not supplied to the solenoid 23 a of the electromagnetic proportionalvalve 23, the regulator 22 and the tank 15 are connected to each other.On the other hand, when a current is supplied to the solenoid 23 a,communication between the regulator 22 and the tank 15 is closed, andthe regulator 22 and the pilot pump are connected to each other.Further, in accordance with a current supplied to the solenoid 23 a, theopening degree between the regulator 22 and the pilot pump increases,and the opening degree between the regulator 22 and the tank decreases.

The electromagnetic proportional valve 23 configured as above outputs tothe regulator 22 the pilot pressure p corresponding to the currentsupplied to the solenoid 23 a. With this, the servo piston of theregulator 22 moves to a position corresponding to the discharge volumecommand current, and the swash plate 21 a tilts at the tilting anglecorresponding to the position of the servo piston. Therefore, theoperating oil is discharged from the hydraulic pump 21 to the mainpassage 16 at the discharge flow rate corresponding to the dischargevolume command current. The plurality of flow rate control devices 12are connected to the main passage 16 in parallel. In the presentembodiment, three flow rate control devices 12 are connected to the mainpassage 16 in parallel.

The three flow rate control devices 12 are provided so as to correspondto respective hydraulic actuators. The hydraulic excavator of thepresent embodiment includes three cylinders, for convenience ofexplanation. To be specific, the hydraulic excavator includes a boomcylinder configured to move the boom, an arm cylinder configured to movethe arm, and a bucket cylinder configured to move the bucket. The threeflow rate control devices 12 correspond to the respective hydrauliccylinders. Each flow rate control device 12 controls the flow directionand flow rate of the operating oil flowing through the correspondinghydraulic cylinder. These three flow rate control devices 12 arebasically the same in configuration as one another except that targetsto which the three flow rate control devices 12 correspond are differentfrom one another. Therefore, the following will just describe theconfiguration of a boom flow rate control device 12 corresponding to theboom cylinder located at the most upstream side as shown in FIG. 1,detailed explanations of the configurations of the other two flow ratecontrol devices that are an arm flow rate control device and a bucketflow rate control device are omitted since the explanation of theconfiguration of the boom flow rate control device 12 is referable.

The flow rate control device 12 includes a flow control valve 25 and apair of electromagnetic proportional valves 26L and 26R. The flowcontrol valve 25 controls the flow direction and flow rate of theoperating oil supplied to the boom cylinder. More specifically, the flowcontrol valve 25 is connected to the main passage 16 and also connectedto the tank 15 through a tank passage 17. The flow control valve 25 isconnected to the boom cylinder through a rod-side passage 18 and ahead-side passage 19. The rod-side passage 18 is connected to a rod-sideport of the boom cylinder, and the head-side passage 19 is connected toa head-side port of the boom cylinder. Therefore, the boom cylindercontracts by supplying the operating oil to the rod-side passage 18 anddischarging the operating oil from the head-side passage 19. Incontrast, the boom cylinder expands by discharging the operating oilfrom the rod-side passage 18 and supplying the operating oil to thehead-side passage 19.

The flow control valve 25 includes a spool 25 a and changes connectionstatuses of the four passages 16 to 19 in accordance with the positionof the spool 25 a. To be specific, when the spool 25 a is located at aneutral position M, all the four passages 16 to 19 are blocked. When thespool 25 a moves to a first offset position L, the rod-side passage 18is connected to the main passage 16, and the head-side passage 19 isconnected to the tank passage 17. When the spool 25 a moves to a secondoffset position R, the rod-side passage 18 is connected to the tankpassage 17, and the head-side passage 19 is connected to the mainpassage 16. Further, the opening degrees of the four passages 16 to 19change in accordance with the position of the spool 25 a. With this, theflow control valve 25 can supply the operating oil to the boom cylinderat the flow rate corresponding to the position of the spool 25 a. To bespecific, the boom cylinder can be moved at a speed corresponding to theposition of the spool 25 a. Pilot pressure pL and pilot pressure pR areapplied to the spool 25 a so as to act against each other, and the spool25 a having such function moves to a position corresponding todifferential pressure between the pilot pressure pL and the pilotpressure pR. In order to apply the pilot pressure pL and the pilotpressure pR to the spool 25 a, the pair of electromagnetic proportionalvalves 26L and 26R are provided at the flow control valve 25.

The pair of electromagnetic proportional valves 26L and 26R are directproportion type electromagnetic proportional valves that are similar inconfiguration to each other. The electromagnetic proportional valve 26Loutputs the pilot pressure pL corresponding to an operating commandcurrent input thereto, and the electromagnetic proportional valve 26Routputs the pilot pressure pR corresponding to an operating commandcurrent input thereto. More specifically, the electromagneticproportional valves 26L and 26R are connected to the flow control valve25, the tank 15, and the pilot pump (not shown). Each of theelectromagnetic proportional valves 26L and 26R includes a solenoid 26 aand adjusts a connection status between the tank 15 and the flow controlvalve 25, a connecting status between the pilot pump and the flowcontrol valve 25, an opening degree between the tank 15 and the flowcontrol valve 25, and an opening degree between the pilot pump and theflow control valve 25 in accordance with a current supplied to thesolenoid 26 a. To be specific, the electromagnetic proportional valve26L has the same function as the electromagnetic proportional valve 23of the hydraulic pump device 11 and outputs the pilot pressure pLcorresponding to the operating command current supplied thereto, and theelectromagnetic proportional valve 26R has the same function as theelectromagnetic proportional valve 23 of the hydraulic pump device 11and outputs the pilot pressure pR corresponding to the operating commandcurrent supplied thereto. With this, the spool 25 a of the flow controlvalve 25 moves to a position corresponding to the operating commandcurrent, and the operating oil is supplied to the boom cylinder in theflow direction corresponding to the operating command current at theflow rate corresponding to the operating command current. To bespecific, the flow control valve 25 can make the boom cylinder expandand contract in a direction corresponding to the operating commandcurrent at a speed corresponding to the operating command current. Inorder to adjust the flow rate of the operating oil supplied to thehydraulic cylinders including the boom cylinder, the bleed-off valve 13is connected to the main passage 16.

The bleed-off valve 13 is an electromagnetic proportional valve. Thebleed-off valve 13 has a function of discharging to the tank 15 theoperating oil flowing through the main passage 16, i.e., has a functionof performing bleed-off. The bleed-off valve 13 having such functionincludes a solenoid 13 a, and a bleed-off command current is input tothe solenoid 13 a. When the bleed-off command current is input to thesolenoid 13 a, the bleed-off valve 13 adjusts an opening degree betweenthe main passage 16 and the tank 15 in accordance with the bleed-offcommand current. With this, the bleed-off of the operating oil can beperformed at the flow rate corresponding to the bleed-off commandcurrent, and this can adjust the flow rate of the operating oil flowingthrough the main passage 16. In order to input the bleed-off commandcurrent to the bleed-off valve 13 having such function, the control unit1 is electrically connected to the bleed-off valve 13.

Control Unit

The control unit 1 shown in FIG. 2 includes a CPU (Central ProcessingUnit), a ROM (Read Only Memory), a RAM (Random Access Memory), and thelike (all not shown). The ROM stores programs executed by the CPU,various fixed data, and the like. The programs executed by the CPU arestored in various storage mediums, such as flexible disks, CD-ROMs, andmemory cards, and are installed to the ROM from such storage mediums.The RAM configured as above temporarily stores data necessary whenexecuting the programs. The control unit 1 is electrically connected tothe solenoid 13 a of the bleed-off valve 13, the solenoid 23 a of theelectromagnetic proportional valve 23 of the hydraulic pump device 11,and the solenoids 26 a of the pair of electromagnetic proportionalvalves 26R and 26L. In order to control the operations of the valves 13,23, 26R, and 26L, the control unit 1 includes a control device 31.

The control device 31 is connected to an operating device (not shown),and the operating device includes three operating levers respectivelycorresponding to the boom, the arm, and the bucket. When the operatinglever is operated, the operating device outputs to the control device 31an operation command corresponding to an operation direction andoperation amount of the operating lever. Then, the control device 31supplies a command current to the solenoid 13 a, 23 a, or 26 a inaccordance with the operation command input thereto. With this, thecorresponding hydraulic cylinder expands or contracts in a directioncorresponding to the operation direction of the operating lever at aspeed corresponding to the operation amount of the operating lever. Thecontrol device 31 moves the hydraulic cylinders by controlling theoperations of the valves 13, 23, 26R, and 26L as above.

The control device 31 selects a normal mode or a restriction mode as anoperating mode of the hydraulic driving apparatus 2. In the restrictionmode, the function of the hydraulic driving apparatus 2 is restricted(for example, upper limits of the pilot pressures p, pL, and pR whichcan be output from the proportional valves 23, 26R, and 26L are setlow), and therefore, maximum outputs of the hydraulic cylinders arerestricted. On the other hand, in the normal mode, the functions of thevalves 23, 26R, and 26L are not restricted, and therefore, the hydrauliccylinders can maximally exert their functions (i.e., each hydrauliccylinder can output a maximum output set at the time of designing).These two modes are switched in accordance with the hydraulic pumpdevice 11 mounted on the hydraulic excavator. More specifically, whenthe hydraulic pump device 11 mounted is not a proper product (i.e., agenuine product) or is not replaced properly, the control device 31selects the restriction mode. In order to determine whether to switchthe operating mode to the restriction mode, the control unit 1 performsindividual identification of the hydraulic pump device 11 mounted on thehydraulic excavator (i.e., individual identification of theelectromagnetic proportional valve 23 of the hydraulic pump device 11).In order to perform the individual identification of the hydraulic pumpdevice 11 based on the electromagnetic proportional valve 23, thecontrol unit 1 includes an electromagnetic valve identification device32.

Electromagnetic Valve Identification Device

In order to perform the individual identification of the electromagneticproportional valve 23, the electromagnetic valve identification device32 measures a resistance value and inductance of the solenoid 23 a ofthe electromagnetic proportional valve 23. Regarding the resistancevalues of the solenoids 23 a, the resistance values of the solenoids ofthe electromagnetic proportional valves of the same type vary little. Onthe other hand, regarding the inductances of the solenoids 23 a, theinductance of each solenoid 23 a has a specific value. However, in manycases, even when the electromagnetic proportional valves are of the sametype (i.e., the solenoids are the same in winding number and wirediameter as one another), the inductances of the respective solenoids 23a of the electromagnetic proportional valves have different numericalvalues due to the shapes, size variations, and the like of magneticbodies arranged around the electromagnetic proportional valves. To bespecific, the solenoids 23 a vary. Therefore, the individualidentification of the electromagnetic proportional valve 23 can beperformed based on the resistance value and the inductance. In order tospecify the type of the electromagnetic proportional valve and performthe individual identification of the electromagnetic proportional valve,the electromagnetic valve identification device 32 includes an LCRmeasuring circuit 41, a calculating portion 42, a storage portion 43, aresistance measuring portion 44, and a determining portion 45. The LCRmeasuring circuit 41 is one example of an inductance measuring circuitand measures the inductance of the solenoid 23 a of the electromagneticproportional valve 23. The LCR measuring circuit 41 is constituted by acircuit connected to the electromagnetic proportional valve 23 by, forexample, a four-terminal method as shown in FIG. 3. A connection methodand circuit configuration adopted in the LCR measuring circuit 41 arenot limited to those shown in FIG. 3. A known circuit capable ofmeasuring the inductance of the solenoid 23 a of the electromagneticproportional valve 23 may be adopted.

The LCR measuring circuit 41 and the control device 31 are formed on asingle substrate to constitute the control unit 1. It should be notedthat the LCR measuring circuit 41 does not necessarily have to be formedon the substrate on which the control device 31 is formed, and the LCRmeasuring circuit 41, the below-described calculating portion 42, andthe below-described storage portion 43 may be configured as a differentdevice (for example, an LCR meter). Further, the control unit 1including the substrate on which the LCR measuring circuit 41 and thecontrol device 31 are formed includes interfaces 1 a to 1 d, and thesolenoids 13 a, 23 a, and 26 a are electrically connected to the controlunit 1 by connecting harnesses 13 b, 23 b, and 26 b to the interfaces 1a to 1 d. The interfaces 1 a to 1 d are connected to the control device31 through separate signal wires. For example, the harness 23 b of theelectromagnetic proportional valve 23 of the hydraulic pump device 11 isconnected to the interface 1 a, and the control device 31 is connectedto the interface 1 a through signal wires 1 e and 1 f. The LCR measuringcircuit 41 is connected to the signal wires 1 e and 1 f throughbelow-described four terminals Hc, Hp, Lp, and Lc. Hereinafter, theconfiguration of the LCR measuring circuit 41 will be described in moredetail.

The LCR measuring circuit 41 includes an oscillator 51, acurrent-voltage converter 52, and a vector voltmeter 53. The oscillator51 generates an alternating current of a predetermined frequency (forexample, 100 Hz) in accordance with a command from the control device 31and includes an internal resistance Rs. The oscillator 51 includes afirst terminal Hc, and the first terminal Hc is connected to the firstsignal wire 1 e. On the other hand, a second terminal Lc of thecurrent-voltage converter 52 is connected to the second signal wire 1 f.The current-voltage converter 52 includes a reference resistance 52 aand a control amplifier 52 b. While suppressing an influence of a straycapacitance 54, the current-voltage converter 52 converts thealternating current, flowing through the solenoid 23 a of theelectromagnetic proportional valve 23, into a voltage such that thevoltage is detectable. To be specific, a voltage differencecorresponding to the alternating current flowing through the solenoid 23a of the electromagnetic proportional valve 23 is generated across thereference resistance 52 a, and the voltage applied to the referenceresistance 52 a is measured by the vector voltmeter 53.

More specifically, the vector voltmeter 53 includes two voltmeters 53 aand 53 b. The first voltmeter 53 a is connected to the first signal wire1 e through a third terminal Hp and connected to the second signal wireif through a fourth terminal Lp. With this, the first voltmeter 53 ameasures a voltage V1 applied to the solenoid 23 a of theelectromagnetic proportional valve 23. The second voltmeter 53 b isconnected to portions in front of and behind the reference resistance 52a and measures a voltage V2 applied to the reference resistance 52 a.The inductance of the solenoid 23 a can be measured based on the twovoltages V1 and V2 measured as above, and the measured voltages V1 andV2 and the alternating current output from the oscillator 51 are outputto the calculating portion 42.

The calculating portion 42 refers to the alternating current output fromthe oscillator 51 and calculates the inductance of the solenoid 23 abased on the two voltages V1 and V2 measured by the vector voltmeter 53.The calculated inductance is stored in the storage portion 43 shown inFIG. 2. In addition to the inductance, the storage portion 43 stores theresistance value of the solenoid 23 a. In order to measure theresistance value, the electromagnetic valve identification device 32includes the resistance measuring portion 44. The resistance measuringportion 44 measures the resistance value of the solenoid 23 a. To bespecific, when a predetermined direct current is supplied from thecontrol device 31 to the solenoid 23 a, the resistance measuring portion44 measures the voltage applied to the solenoid 23 a and calculates theresistance value of the solenoid 23 a based on this voltage and thesupplied direct current. The storage portion 43 stores the calculatedresistance value together with the inductance. With this, the resistancevalue and the inductance can be stored in the storage portion 43 asindividual identification information of the electromagneticproportional valve 23 of the hydraulic pump device 11, i.e., individualidentification information of the hydraulic pump device 11. Further,each of the stored inductance and the stored resistance value is storedas a reference value or an actually measured value in accordance withthe mode selected when below-described calculations are performed. Thereference value and the actually measured value stored as above are usedin the determining portion 45 as below.

The determining portion 45 mainly determines whether or not theelectromagnetic proportional valve 23 has been replaced, i.e., whetheror not the hydraulic pump device 11 has been replaced. To be specific,the determining portion 45 performs two determinations that are agenuine product determination and a replacement determination. In thegenuine product determination, whether or not the electromagneticproportional valve 23 has been replaced, i.e., whether or not thehydraulic pump device 11 has been replaced is determined based on thefollowing determination criterion. To be specific, the determinationcriterion is whether or not the actually measured resistance valuestored as the actually measured value is a numerical value that fallswithin a predetermined allowable range (i.e., a resistance valueallowable range) and whether or not the actually measured inductancestored as the actually measured value is a numerical value that fallswithin a predetermined allowable range (i.e., an inductance allowablerange). For example, in the case of the electromagnetic proportionalvalves 23 that are the genuine products, the solenoids 23 a aremanufactured within a predetermined manufacturing error (tolerance).Therefore, the measured numerical values of the resistance values andinductances do not exceed the manufacturing error with exceptions, suchas breakdown. Therefore, when the actually measured resistance valuefalls outside the allowable range set in accordance with themanufacturing error, and the actually measured inductance falls outsidethe allowable range set in accordance with the manufacturing error, thedetermining portion 45 determines that the hydraulic pump device 11 isnot the genuine product. On the other hand, when the actually measuredresistance value falls within the allowable range, and the actuallymeasured inductance falls within the allowable range, the determiningportion 45 determines that the hydraulic pump device 11 is the genuineproduct.

On the other hand, in the replacement determination, the reference valueand the actually measured measurement value are compared with eachother, and based on the determination criterion that is whether or notthe reference value and the actually measured measurement value aredifferent from each other, whether or not the electromagneticproportional valve 23 has been replaced is determined, i.e., whether ornot the hydraulic pump device 11 has been replaced is determined. To bespecific, the type of the electromagnetic proportional valve 23 can bespecified by the resistance value of the solenoid 23 a of theelectromagnetic proportional valve 23, and the individual identity ofthe electromagnetic proportional valve 23 can be determined by theinductance of the solenoid 23 a of the electromagnetic proportionalvalve 23. With this, whether or not the same electromagneticproportional valve 23 is being continuously mounted can be determined bycomparison between the actually measured measurement value and thereference value, and based on the result of this determination, whetheror not the electromagnetic proportional valve 23 has been replaced,i.e., whether or not the hydraulic pump device 11 has been replaced canbe determined. As above, the determining portion 45 performs the genuineproduct determination and the replacement determination to determinewhether or not the hydraulic pump device 11 is the genuine product andwhether or not the hydraulic pump device 11 has not been replaced. Whenthe hydraulic pump device 11 is an improper product, or when thehydraulic pump device 11 has been replaced, the control device 31restricts the movements of the hydraulic cylinders.

As above, the control unit 1 performs the genuine product determinationand the replacement determination based on the reference values and theallowable ranges. As described above, the control unit 1 stores thereference values (a reference resistance value and a referenceinductance) and the actually measured measurement values (the actuallymeasured resistance value and the actually measured inductance) inaccordance with the below-described mode. In order to select such mode,a measurement mode selector 46 is electrically connected to the controlunit 1. The measurement mode selector 46 is constituted by, for example,an operation panel and can select a reference value measurement mode oran actually measured value measurement mode. The reference valuemeasurement mode is a mode in which the reference resistance value andthe reference inductance are measured in order to store the referenceresistance value and the reference inductance in the storage portion 43.To be specific, in the reference value measurement mode, the measuredresistance value and inductance are stored in the storage portion 43 asthe individual identification information of the hydraulic pump device11 to be used. In the control unit 1, the hydraulic pump device 11 to beused is registered by storing the reference values. In the presentembodiment, selection of the reference value measurement modecorresponds to satisfaction of a reference value setting condition. Onthe other hand, the actually measured value measurement mode is a modein which: the actually measured resistance value and the actuallymeasured inductance are measured; and the genuine product determinationand the replacement determination are executed based on the actuallymeasured resistance value and the actually measured inductance, and is amode in which the individual identification of the hydraulic pump device11 is performed.

As above, the measurement mode selector 46 can select any one of thesetwo modes. When one of the two modes is selected, the measurement modeselector 46 gives a command to the control device 31 such thatprocessing corresponding to the selected mode is performed. It should benoted that it is preferable that in order to prevent the registeredhydraulic pump device 11 from being changed unreasonably, the referencevalue measurement mode be not selectable without inputting a presetpassword or the like. To be specific, it is preferable that at placesother than manufacturing factories and certified factories, thereference value measurement mode be not selectable, and the actuallymeasured value measurement mode be selected at all times. With this, itis possible to prevent a case where the reference values are changed,and the electromagnetic proportional valve 23 is made to look as if ithas not been replaced. Thus, it is possible to prevent a case where thehydraulic pump device 11 is replaced by an improper method at placesother than the manufacturing factories and the certified factories. Asabove, the control unit 1 registers the hydraulic pump device 11 to beused or performs the individual identification of the hydraulic pumpdevice 11 to be used, in accordance with the selection of the mode bythe measurement mode selector 46. Hereinafter, the procedure of theindividual identification processing of the control unit 1 will bedescribed with reference to the flow charts of FIGS. 4 to 6.

Individual Identification Processing

When a main switch of the hydraulic excavator is turned on, and thecontrol unit 1 is supplied with electric power, the individualidentification processing by the control unit 1 starts, and the processproceeds to Step 51 as shown in FIG. 4. In Step S1 that is a measurementmode determining step, whether or not the mode selected by themeasurement mode selector 46 is the reference value measurement mode isdetermined. When it is determined that the mode selected is thereference value measurement mode, the process proceeds to Step S2. InStep S2 that is a reference value measuring step, reference valuemeasurement processing shown in FIG. 5 is executed. The reference valuemeasurement processing is processing in which the reference resistancevalue and reference inductance of the solenoid 23 a are measured andstored in the storage portion 43. When the reference value measurementprocessing is executed, the process proceeds to Step S11.

In Step S11 that is a reference resistance value measuring step, thereference resistance value of the solenoid 23 a of the electromagneticproportional valve 23 of the hydraulic pump device 11 is measured. To bespecific, the control device 31 supplies a predetermined direct currentto the solenoid 23 a of the electromagnetic proportional valve 23 andmakes the resistance measuring portion 44 measure the voltage applied tothe solenoid 23 a and calculate the reference resistance value of thesolenoid 23 a. After the reference resistance value is calculated, theprocess proceeds to Step S12. In Step S12 that is a reference inductancemeasuring step, the reference inductance of the solenoid 23 a of theelectromagnetic proportional valve 23 of the hydraulic pump device 11 ismeasured. To be specific, the control device 31 makes the oscillator 51of the LCR measuring circuit 41 output the alternating current and makesthe vector voltmeter 53 measure the voltages V1 and V2. Further, thecontrol device 31 makes the calculating portion 42 calculate thereference inductance of the solenoid 23 a based on the measured voltagesV1 and V2. After the reference inductance is calculated, the processproceeds to Step S13.

In Step S13 that is a reference value storing step, the referenceresistance value measured in Step S11 and the reference inductancemeasured in Step S12 are stored in the storage portion 43. The referenceresistance value and the reference inductance stored as above are storedin the storage portion 43 as the individual identification informationof the hydraulic pump device 11, and with this, an electricalcharacteristic of the hydraulic pump device 11 mounted is registered inthe control unit 1. Then, the process proceeds to Step S14. In Step S14that is a mode terminating step, the control device 31 terminates thereference value measurement mode. With this, the reference valuemeasurement processing is terminated, and the process returns to Step S1from Step S2. Further, when it is determined in Step S1 that the modeselected is the actually measured value measurement mode, the processproceeds to Step S3.

In Step S3 that is a measurement standby step, whether or not apredetermined time has elapsed since the measurement of the resistancevalue and inductance is determined. To be specific, the control device31 measures an elapsed time since the termination of the above-describedreference value measurement processing or the termination of thebelow-described actually measured value measurement processing anddetermines whether or not the elapsed time is a predetermined time ormore. When the elapsed time is less than the predetermined time, theprocess returns to Step S1. When the elapsed time is the predeterminedtime or more, the process proceeds to Step S4. In Step S4 that is anactually measured value measuring step, the actually measured valuemeasurement processing shown in FIG. 6 is executed. The actuallymeasured value measurement processing is processing in which theresistance value (i.e., the actually measured resistance value) andinductance (i.e., the actually measured inductance) of the solenoid 23 aare measured as the actually measured measurement values to be comparedwith the reference values. When the actually measured value measurementprocessing is executed, the process proceeds to Step S21.

In Step S21 that is an actually measured resistance value measuringstep, the actually measured resistance value of the solenoid 23 a of theelectromagnetic proportional valve 23 of the hydraulic pump device 11 ismeasured. To be specific, the control device 31 supplies a predetermineddirect current to the solenoid 23 a of the electromagnetic proportionalvalve 23 and makes the resistance measuring portion 44 measure thevoltage applied to the solenoid 23 a and calculate the actually measuredresistance value of the solenoid 23 a. After the actually measuredresistance value is calculated, the process proceeds to Step S22. InStep S22 that is an actually measured inductance measuring step, theactually measured inductance of the solenoid 23 a of the electromagneticproportional valve 23 of the hydraulic pump device 11 is measured. To bespecific, the control device 31 makes the oscillator 51 of the LCRmeasuring circuit 41 output the alternating current and makes the vectorvoltmeter 53 measure the voltages V1 and V2. Further, the control device31 makes the calculating portion 42 calculate the actually measuredinductance of the solenoid 23 a based on the measured voltages V1 andV2. After the actually measured inductance is calculated, the processproceeds to Step S23.

In Step S23 that is an actually measured measurement value storing step,the actually measured resistance value measured in Step S21 and theactually measured inductance measured in Step S22 are stored in thestorage portion 43. To be specific, the actually measured resistancevalue and the actually measured inductance are stored in the storageportion 43 as the individual identification information of the hydraulicpump device 11 mounted currently. Then, the process proceeds to StepS24.

In Step S24 that is a genuine product determining step, based on theactually measured measurement values stored in Step S23, the determiningportion 45 executes the genuine product determination to determinewhether or not the hydraulic pump device 11 mounted currently is thegenuine product. To be specific, the determining portion 45 determineswhether or not the actually measured resistance value is a numericalvalue that falls within the predetermined resistance value allowablerange and also determines whether or not the actually measuredinductance is a numerical value that falls within the predeterminedinductance allowable range. When it is determined that both the actuallymeasured resistance value and the actually measured inductance are therespective numerical values that fall within the respective allowableranges, the process proceeds to Step S25.

In Step S25 that is a replacement determining step, based on thereference values stored in the reference value measurement processingand the actually measured measurement values stored in Step S24, thedetermining portion 45 executes the replacement determination todetermine whether or not the hydraulic pump device 11 mounted currentlyis a hydraulic pump device that has been mounted after the execution ofthe reference value measurement processing. To be specific, thedetermining portion 45 compares the reference resistance value with theactually measured resistance value and determines whether or not thereference resistance value and the actually measured resistance valueare different from each other (i.e., whether or not the referenceresistance value and the actually measured resistance value coincidewith each other). Further, the determining portion 45 compares thereference inductance with the actually measured inductance anddetermines whether or not the reference inductance and the actuallymeasured inductance are different from each other (i.e., whether or notthe reference inductance and the actually measured inductance coincidewith each other). It should be noted that a case where the referencevalue and the actually measured value coincide with each other denotesnot only a case where the reference value and the actually measuredvalue completely coincide with each other but also a case where theactually measured value falls within a predetermined range with respectto the reference value. To be specific, when a difference between thereference value and the actually measured value falls within apredetermined threshold, it is determined that the reference value andthe actually measured value coincide with each other (the referencevalue and the actually measured value are not different from eachother). As above, when it is determined that the actually measuredresistance value and the actually measured inductance are not differentfrom the respective reference values, i.e., coincide with the respectivereference values, the process proceeds to Step S26.

In Step S26 that is a normal mode setting step, the operating mode ofthe hydraulic driving apparatus 2 is set to (or maintained in) thenormal mode. With this, the control device 31 allows the hydraulicdriving apparatus 2 to maximally exert the function. After the operatingmode is set the normal mode as above, the actually measured valuemeasurement processing terminates. On the other hand, when thedetermining portion 45 determines in Step S24 of the actually measuredvalue measurement processing that the actually measured resistance valueor the actually measured inductance does not fall within thecorresponding allowable range, or when the determining portion 45determines by comparison in Step S25 that the reference inductance andthe actually measured inductance are different from each other, theprocess proceeds to Step S27.

In Step S27 that is a restriction mode setting step, the operating modeof the hydraulic driving apparatus 2 is set to (or maintained in) therestriction mode. With this, the function of the hydraulic drivingapparatus 2 is restricted, and the maximum outputs that can be output bythe respective hydraulic cylinders are restricted. To be specific, whenthe hydraulic pump device 11 that is a non-genuine product is mounted,or when the hydraulic pump device 11 is replaced through a procedurethat is not the proper procedure, the hydraulic pump device 11 can beoperated only at a low-level output. Therefore, it is possible toprevent a case where when the performance of the hydraulic drivingapparatus 2 is made low since the hydraulic pump device 11 that is anon-genuine product is mounted or when the hydraulic pump device 11 isreplaced through a procedure that is not the proper procedure, thehydraulic driving apparatus 2 is made to perform overwork that is morethan the performance, and as a result, the hydraulic driving apparatus 2breaks, for example. After the operating mode is set to the restrictionmode as above, the actually measured value measurement processingterminates. It should be noted that the restriction mode continues untilthe process proceeds to Step S26, and the operating mode is set to thenormal mode. To be specific, the function of the hydraulic drivingapparatus 2 is restricted as long as it is determined in Step S24 thatthe actually measured resistance value or the actually measuredinductance is a numerical value that falls outside the correspondingallowable range, or it is determined by comparison in Step S25 that thereference inductance and the actually measured inductance are differentfrom each other. On the other hand, by replacing the hydraulic pumpdevice 11 with the genuine product at a certified factory or the likeand resetting the reference values in the reference value measurementprocessing, the restriction mode can be canceled, and the operating modecan be reset to the normal mode.

As above, when the operating mode of the hydraulic driving apparatus 2is set to the normal mode or the restriction mode, the actually measuredvalue measurement processing is terminated. After the actually measuredvalue measurement processing is terminated, the process returns to StepS1 from Step S4, and the determination of the measurement mode isperformed again. Therefore, in the individual identification processing,the actually measured value measurement processing is repeatedlyperformed for every predetermined time until the reference valuemeasurement mode is selected. The individual identification processingis terminated by turning off the main switch of the hydraulic excavator.

As above, by mounting the electromagnetic valve identification device 32on the industrial vehicle, the individual identification of theelectromagnetic proportional valve 23 and the individual identificationof the hydraulic pump device 11 including the electromagneticproportional valve 23 can be performed. Therefore, it is unnecessary toattach IC chips to the electromagnetic proportional valves 23 and thehydraulic pump devices 11 mounted on the industrial vehicles or attachIDs to the electromagnetic proportional valves 23 and the hydraulic pumpdevices 11 mounted on the industrial vehicles to manage theelectromagnetic proportional valves 23 and the hydraulic pump devices11, in order to perform the individual identification of theelectromagnetic proportional valves 23. Thus, the manufacturing cost canbe suppressed. Further, since not only the inductance of the solenoid 23a but also the resistance value of the solenoid 23 a are used, theindividual identification of the electromagnetic proportional valve 23and the individual identification of the hydraulic pump device 11including the electromagnetic proportional valve 23 can be performedmore accurately than when only the inductance is used.

Further, by comparing the measured inductance with the referenceinductance, the control unit 1 can determine whether or not theelectromagnetic proportional valve 23 has been replaced. Therefore,whether or not the hydraulic pump device 11 has been replaced can bedetermined by a simple configuration without attaching IC chips to thehydraulic pump devices 11 or attaching IDs to the hydraulic pump devices11 to manage the hydraulic pump devices 11. Especially, whether or notthe same electromagnetic proportional valve 23 is being continuouslymounted can be determined based on whether or not the referenceinductance and the actually measured inductance are different from eachother. When it is determined that the same electromagnetic proportionalvalve 23 is not being continuously mounted, it can be determined thatthe electromagnetic proportional valve 23 has been replaced at a certaintime point. Therefore, whether or not the replacement work has beenperformed can be surely determined. On this account, whether or not thereplacement work has been performed can be determined, and the functionof the hydraulic driving apparatus 2 can be restricted when thereplacement has been performed through a procedure that is not theproper procedure.

When the electromagnetic proportional valve 23 has been replaced, thecontrol unit 1 can execute the reference value measurement processing toreset the reference inductance and the reference resistance value (i.e.,the reference values). On the other hand, when the electromagneticproportional valve 23 has been replaced in a state where the referencevalue measurement processing cannot be executed, the reference valuescannot be changed, and the function of the hydraulic driving apparatus 2is restricted continuously. Therefore, by realizing the reference valuemeasurement processing by which the replacement can be performed throughthe proper procedure at the certified factory or the like, the hydraulicdriving apparatus 2 can be made to maximally exert the function onlywhen the electromagnetic proportional valve 23 is replaced through theproper procedure. Further, since the reference values cannot be resetwithout executing the reference value measurement processing, it ispossible to prevent a case where the reference values are changed, andthe electromagnetic proportional valve 23 is made to look as if it hasnot been replaced.

Embodiment 2

The control unit 1A of Embodiment 2 is similar in configuration to thecontrol unit 1 of Embodiment 1. Therefore, components of the controlunit 1A of Embodiment 2 which are different from the components of thecontrol unit 1 of Embodiment 1 will be mainly described. The samereference signs are used for the same components, and explanationsthereof are omitted.

As shown in FIG. 7, the control unit 1A of Embodiment 2 includes anelectromagnetic valve identification device 32A and the control device31, and the electromagnetic valve identification device 32A includes thestorage portion 43, the resistance measuring portion 44, and adetermining portion 45A. To be specific, in order to measure theresistance value of the solenoid 23 a, the control unit 1A supplies apredetermined direct current from the control device 31 to the solenoid23 a. At this time, the resistance measuring portion 44 measures thevoltage applied to the solenoid 23 a and calculates the resistance valueof the solenoid 23 a based on this voltage and the supplied directcurrent. The storage portion 43 stores the calculated resistance valueas the individual identification information of the electromagneticproportional valve 23 of the hydraulic pump device 11, i.e., theindividual identification information of the hydraulic pump device 11.The stored resistance value is stored as the reference resistance valueor the actually measured resistance value in accordance with theselected mode. The reference resistance value and the actually measuredresistance value stored as above are used when determining whether ornot the electromagnetic proportional valve 23 has been replaced, i.e.,whether or not the hydraulic pump device 11 has been replaced.

To be specific, the type of the electromagnetic proportional valve 23can be specified by the resistance value of the solenoid 23 a, andwhether or not the same electromagnetic proportional valve 23 is beingcontinuously mounted can be determined by comparison between the storedreference resistance value and the stored actually measured resistancevalue. Therefore, based on the result of this determination, whether ornot the electromagnetic proportional valve 23 has been replaced, i.e.,whether or not the hydraulic pump device 11 has been replaced can bedetermined. On this account, the determining portion 45A determineswhether or not the electromagnetic proportional valve 23 has beenreplaced, i.e., whether or not the hydraulic pump device 11 has beenreplaced, based on the determination criterion that is whether or notthe stored reference resistance value and the stored actually measuredresistance value are different from each other. As above, thedetermining portion 45A determines by the replacement determinationwhether or not the hydraulic pump device 11 has been replaced. When theimproper product is used, or when the hydraulic pump device 11 has beenreplaced, the control device 31 restricts the movements of the hydrauliccylinders.

As above, in order to select the reference value measurement mode or theactually measured value measurement mode, the control unit 1A iselectrically connected to the measurement mode selector 46 and canselect the mode by the measurement mode selector 46. In the referencevalue measurement mode, the resistance value measured by the resistancemeasuring portion 44 is stored in the storage portion 43 as thereference resistance value, i.e., the measured resistance value isstored in the storage portion 43 as the individual identificationinformation of the hydraulic pump device 11. On the other hand, in theactually measured value measurement mode, the above-describedreplacement determination is performed based on the actually measuredresistance value and the prestored reference resistance value. As withthe control unit 1 of Embodiment 1, it is preferable that: the referencevalue measurement mode be not selectable at places other than themanufacturing factories, the certified factories, and the like; and theactually measured value measurement mode be selected at all times.

As above, the control unit 1A registers the hydraulic pump device 11 tobe used or performs the individual identification of the hydraulic pumpdevice 11 to be used in accordance with the mode selection performed bythe measurement mode selector 46. It should be noted that the procedureof the individual identification processing of the control unit 1A issimilar to the procedure of the individual identification processing ofthe control unit 1 of Embodiment 1, and the following will mainlydescribe differences.

According to the individual identification processing performed by thecontrol unit 1A, when the reference resistance value of the solenoid 23a is measured in Step S11 of the reference value measurement processing,the process proceeds to Step S13, and the measured reference resistancevalue is stored in the storage portion 43 as the individualidentification information of the hydraulic pump device 11. Further,when the actually measured resistance value of the solenoid 23 a of theelectromagnetic proportional valve 23 is measured in Step S21 of theactually measured value measurement processing, the process proceeds toStep S23, and the obtained actually measured resistance value is storedin the storage portion 43 as the individual identification informationof the hydraulic pump device 11. After the actually measured resistancevalue is stored, it is confirmed in Step 24 that the actually measuredresistance value falls within an allowable value. After it is confirmedthat the actually measured resistance value falls within the allowablevalue, the process proceeds to Step S25. The reference resistance valuestored in the reference value measurement processing and the actuallymeasured resistance value stored in Step S24 are compared with eachother, and whether or not the hydraulic pump device 11 mounted currentlyis a hydraulic pump device that has been mounted after the execution ofthe reference value measurement processing is determined. When thehydraulic pump device 11 has not been replaced, the process proceeds toStep S26, and the normal mode is set. When the hydraulic pump device 11has been replaced, the process proceeds to Step S27, and the operatingmode of the hydraulic driving apparatus 2 is set to (or maintained in)the restriction mode.

As above, the control unit 1A can determine based on the measuredresistance values whether or not the electromagnetic proportional valve23 has been replaced. More specifically, whether or not the sameelectromagnetic proportional valve 23 is being continuously mounted canbe determined by comparison between the reference resistance value andthe actually measured resistance value. Therefore, whether or not thehydraulic pump device 11 has been replaced can be determined by a simpleconfiguration without attaching IC chips to the hydraulic pump devices11 or attaching IDs to the hydraulic pump devices 11 to manage thehydraulic pump devices 11.

Other than the above, the control unit 1A of Embodiment 2 can obtain thesame operational advantages as the control unit 1 of Embodiment 1.

Other Embodiment

Each of the control units 1 and 1A of Embodiments 1 and 2 regards theelectromagnetic proportional valve 23 of the hydraulic pump device 11 asan identification target. However, the identification target is notnecessarily limited to this. The identification target may be, forexample, the flow rate control device 12 or the bleed-off valve 13. Inthe case of the flow rate control device 12, at least one of theresistance values and inductances of the solenoids 26 a of theelectromagnetic proportional valves 26L and 26R of the flow rate controldevice 12 is measured, and the individual identification of the flowrate control device 12 is performed. In the case of the bleed-off valve13, at least one of the resistance value and inductance of the solenoid13 a of the bleed-off valve 13 is measured, and the individualidentification of the bleed-off valve 13 may be performed. Further, theindividual identification executed by the control units 1 and 1A is notlimited to the individual identification of one electromagneticproportional valve 23 and may be the individual identification of aplurality of electromagnetic proportional valves 13, 23, 26L, and 26R.In this case, the LCR measuring circuit 41 and the resistance measuringportion 44 are connected to the electromagnetic proportional valves 13,23, 26L, and 26R through a switching device and measure the inductanceand the resistance value while switching the measurement targets by theswitching device.

According to the control units 1 and 1A of Embodiments 1 and 2, thetarget for the individual identification is the electromagneticproportional valve. However, the target for the individualidentification is not limited to the electromagnetic proportional valveand is only required to be an electromagnetic type valve including asolenoid, i.e., an electromagnetic valve. Further, the control unit 1measures both the inductance and resistance value of the solenoid 23 abut does not necessarily have to measure both the inductance andresistance value of the solenoid 23 a. To be specific, as with thecontrol unit 1A, only the resistance of the solenoid 23 a may bemeasured and stored as the individual identification information, oronly the inductance of the solenoid 23 a may be measured and stored asthe individual identification information. Further, based on suchindividual identification information, whether or not theelectromagnetic proportional valve 23 has been replaced may bedetermined.

The determining portion 45 of the control unit 1 executes both thegenuine product determination and the replacement determination but doesnot necessarily have to execute both the genuine product determinationand the replacement determination. To be specific, the determiningportion 45 may execute only one of the genuine product determination andthe replacement determination. Further, the control unit 1 may juststore the individual identification information of the electromagneticproportional valve 23 in the storage portion 43 without executing thegenuine product determination and the replacement determination. Withthis, when the hydraulic driving apparatus 2 breaks, whether or not thegenuine product has been used and whether or not the replacement hasbeen properly performed can be determined based on the individualidentification information. Further, the replacement determination isperformed based on the reference inductance measured and stored in thereference value measurement processing, but the reference inductance isnot limited to such value. One example may be such that: the actuallymeasured inductance measured in the previously-performed actuallymeasured value measurement processing is set as the referenceinductance; and the actually measured inductance measured in thepreviously-performed actually measured value measurement processing iscompared with the actually measured inductance measured in themost-recently-performed actually measured value measurement processing.

Further, the LCR measuring circuit does not have to be configured by thefour-terminal method and may be configured by, for example, atwo-terminal method. Further, the control unit 1 restricts the hydraulicdriving apparatus 2 in the same manner between when it is determined inthe genuine product determination that the hydraulic pump device 11 isnot the genuine product and when it is determined in the replacementdetermination that the hydraulic pump device 11 has been replacedimproperly. However, the control unit 1 does not necessarily have tooperate as above. For example, when the electromagnetic valve that isnot the genuine product, the control unit 1 may restrict the maximumoutput (a maximum speed or a maximum propulsive force) of the hydrauliccylinder more strongly than when the electromagnetic valve is thegenuine product but has been replaced improperly. With this, thereplacement using the genuine product can be promoted.

Further, the control units 1 and 1A of Embodiments 1 and 2 are appliedto travelable construction machines and industrial vehicle. However,Embodiments 1 and 2 are not limited to these. For example, the controlunits 1 and 1A of Embodiments 1 and 2 may be applied to fixed industrialmachines.

REFERENCE SIGNS LIST

1, 1A control unit

2 hydraulic driving apparatus

11 hydraulic pump device

13 bleed-off valve (electromagnetic valve)

13 a solenoid

23 electromagnetic proportional valve (electromagnetic valve)

23 a solenoid

26L, 26R electromagnetic proportional valve (electromagnetic valve)

26 a solenoid

31 control device

32, 32A electromagnetic valve identification device

41 LCR measuring circuit (inductance measuring circuit)

42 calculating portion

43 storage portion

44 resistance measuring portion

45, 45A determining portion (replacement determining portion)

46 measurement mode selector

1. An electromagnetic valve identification device mounted on anindustrial machine, such as a construction machine or an industrialvehicle, configured to move a hydraulic actuator to perform work, theelectromagnetic valve identification device comprising: an inductancemeasuring circuit configured to supply an alternating current to asolenoid of an electromagnetic valve of a hydraulic device, thehydraulic device being configured to supply pressure oil to thehydraulic actuator to operate the hydraulic actuator; a calculatingportion configured to calculate an inductance of the solenoid based onthe alternating current supplied to the solenoid by the inductancemeasuring circuit; and a storage portion configured to store thecalculated inductance of the solenoid as individual identificationinformation of the electromagnetic valve.
 2. The electromagnetic valveidentification device according to claim 1, further comprising areplacement determining portion configured to determine whether or notthe electromagnetic valve has been replaced, based on a determinationcriterion in which whether or not the electromagnetic valve has beenreplaced is determined by using the inductance calculated by thecalculating portion.
 3. The electromagnetic valve identification deviceaccording to claim 2, wherein: the determination criterion includeswhether or not a reference inductance of the solenoid and an actuallymeasured inductance of the solenoid are different from each other, thereference inductance being calculated by the calculating portion andstored in the storage portion in advance, the actually measuredinductance being calculated by the calculating portion; and when theactually measured inductance is different from the reference inductance,the replacement determining portion determines that the electromagneticvalve has been replaced.
 4. The electromagnetic valve identificationdevice according to claim 3, wherein: when a predetermined referencevalue setting condition is satisfied, the calculating portion calculatesthe reference inductance of the solenoid; and the storage portion storesthe reference inductance calculated by the calculating portion.
 5. Theelectromagnetic valve identification device according to claim 2,wherein: the determination criterion includes whether or not theactually measured inductance calculated by the calculating portion fallswithin a predetermined allowable range; and when the actually measuredinductance falls outside the allowable range, the replacementdetermining portion determines that the electromagnetic valve has beenreplaced.
 6. The electromagnetic valve identification device accordingto claim 2, further comprising a resistance measuring portion configuredto supply a direct current to the solenoid and measure a resistancevalue of the solenoid, wherein: the determination criterion includeswhether or not a reference resistance value of the solenoid and anactually measured resistance value of the solenoid are different fromeach other, the reference resistance value being measured by theresistance measuring portion in advance, the actually measuredresistance value being measured by the resistance measuring portion; andthe replacement determining portion compares the actually measuredresistance value with the reference resistance value and determineswhether or not the electromagnetic valve has been replaced.
 7. Anelectromagnetic valve identification device mounted on an industrialmachine, such as a construction machine or an industrial vehicle,configured to move a hydraulic actuator to perform work, theelectromagnetic valve identification device comprising: a resistancemeasuring portion configured to supply a direct current to a solenoid ofan electromagnetic valve of a hydraulic device and measure a resistancevalue of the solenoid, the hydraulic device being configured to supplypressure oil to the hydraulic actuator to operate the hydraulicactuator; and a replacement determining portion configured to determinewhether or not the electromagnetic valve has been replaced, based on adetermination criterion in which whether or not the electromagneticvalve has been replaced is determined by using the resistance valuemeasured by the resistance measuring portion.
 8. The electromagneticvalve identification device according to claim 7, wherein thedetermination criterion includes whether or not a reference resistancevalue of the solenoid and an actually measured resistance value of thesolenoid are different from each other, the reference resistance valuebeing measured by the resistance measuring portion in advance, theactually measured resistance value being measured by the resistancemeasuring portion.
 9. A control unit comprising: the electromagneticvalve identification device according to claim 2; and a control devicemounted on the industrial vehicle and configured to supply a current tothe solenoid of the electromagnetic valve to control an operation of theelectromagnetic valve, wherein the control device is configured torestrict the operation of the electromagnetic valve when the replacementdetermining portion determines that the electromagnetic valve has beenreplaced.